Key components of effective contact interventions for reducing public mental health stigma: An updated meta-analysis.

Previous meta-analyses suggest intergroup contact to be effective at reducing public mental health stigma. At the same time, results are mixed regarding intervention and participant characteristics which may strengthen the effect of contact, making it challenging to develop more effective interventions. To address this, we conducted a meta-analysis of 209 published and unpublished articles reporting the effect of contact immediately after the intervention (k = 187, n = 36,477), and in the short- (k = 66, n = 8148) and medium-term (k = 17, n = 2250), on various dimensions of stigma. Several characteristics of these studies were coded and analysed as potential moderators. The effect of contact on stigma was significant at all three timepoints (g = -0.36, -0.33, -0.45, respectively) and on most dimensions of stigma, but the size of the effect significantly varied according to the medium of contact, inclusion of educational information, mental illness of the group member, country, and participant occupation. For example, the effect was larger when multiple mediums of contact were used compared to one, when educational information was included compared to not, when the outgroup member had a severe mental illness compared to a non-severe mental illness, and in non-Western compared to Western countries; and was smaller in community members compared to other groups of participants. These results may inform researchers of gaps in the literature still to be filled, such as involving outgroup members with mental illnesses other than depression and schizophrenia, and may inform recommendations for the development and implementation of contact interventions in the laboratory and real world.